Employee Benefit Plan - Actuarial Assumptions (Details) - Non-U.S. Plan	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Minimum
Actuarial assumptions, benefit obligation
Discount rate, benefit obligation	0.70%	0.70%
Inflation, benefit obligation	1.00%	1.00%
Expected return on plan assets, benefit obligation	1.30%	1.30%
Rate of salary increases, benefit obligation	2.00%	2.00%
Actuarial assumptions, net periodic cost
Discount rate, net periodic benefit cost	0.70%	0.70%
Inflation rate, net period benefit cost	1.00%	1.00%
Expected return on plan assets	1.30%	1.30%
Rate of salary increases, net periodic benefit cost	2.00%	2.00%
Maximum
Actuarial assumptions, benefit obligation
Discount rate, benefit obligation	1.50%	1.60%
Inflation, benefit obligation	1.80%	1.80%
Expected return on plan assets, benefit obligation	2.00%	2.00%
Rate of salary increases, benefit obligation	2.80%	2.80%
Actuarial assumptions, net periodic cost
Discount rate, net periodic benefit cost	1.50%	1.60%
Inflation rate, net period benefit cost	1.80%	1.80%
Expected return on plan assets	2.00%	2.00%
Rate of salary increases, net periodic benefit cost	2.80%	2.80%